Geophysical signatures of fluids in a reactivated Precambrian collisional suture in central India

AbstractThe Central India Tectonic Zone (CITZ) marks the trace of a major suture zone along which the south Indian and the north Indian continental blocks were assembled through subduction-accretion-collision tectonics in the Mesoproterozoic. The CITZ also witnessed the major, plume-related, late Cretaceous Deccan volcanic activity, covering substantial parts of the region with continental flood basalts and associated magmatic provinces. A number of major fault zones dissect the region, some of which are seismically active. Here we present results from gravity modeling along five regional profiles in the CITZ, and combine these results with magnetotelluric (MT) modeling results to explain the crustal architecture. The models show a resistive (more than 2000 Ω·m) and a normal density (2.70 g/cm3) upper crust suggesting dominant tonalite–trondhjemite–granodiorite (TTG) composition. There is a marked correlation between both high-density (2.95 g/cm3) and low-density (2.65 g/cm3) regions with high conductive zones (